Bag filling apparatuses for packing loose material typically use a stationary filling chute positioned over the bag ready to be filled and sealing equipment for sealing the top of the bag once it has been filled with the dusty material. The sealing of the bag is usually performed by melting a top sealing region of the bag thereby obtaining a transverse seam sealing the bag. One problem encounters with such machine is that fluffy dust tends to be ejected from the bag into the surrounding environment and also to accumulate on the inside surface of the bag. Such dust contamination come from the air draft generated when the bag is filled up with the loose material. The air draft activates the dust contained in the material as the bag is filled and allows the dust to stick on the inside surface of the bag. Since the dust generally has a higher melting point than the material from which the bag is made, typically polyethylene, the dust acts as a thermal barrier, thus affecting the seal strength. While many attempts have been made by the industry to successfully prevent dust emission and the contamination of the sealing region of a bag with very dusty materials, the problem remains unsolved.
Thus, there is still presently a need for a bag filling apparatus for filling loose material into a bag that successfully prevents dust contamination of the bag within a sealing zone.
There is also a need for a bag filling apparatus for filling loose material into a bag that successfully prevents dust emission outside the bag during and after the feeding of loose material into the bag.
Known in the art are U.S. Pat. No. 3,928,940 (Fagniart); U.S. Pat. No. 3,707,172 (Obara); U.S. Pat. No. 4,096,894 (Guy); U.S. Pat. No. 4,109,792 (Greenawalt et al.); U.S. Pat. No. 4,182,386 (Alack); U.S. Pat. No. 4,308,710 (Sandberg); U.S. Pat. No. 4,526,214 (McGreggor); U.S. Pat. No. 4,648,432 (Mechalas); U.S. Pat. No. 5,349,996 (McGreggor); U.S. Pat. No. 5,413,157 (McGreggor); U.S. Pat. No. 5,531,252 (Derby et al.); U.S. Pat. No. 5,581,984 (Domke et al.); U.S. Pat. No. 5,704,197 (Gifford); U.S. Pat. No. 6,748,723 (Wadium et al.); and Japan Patent no. 07033257, which disclose various apparatuses and methods for keeping the inside of a bag free from dust in its sealing region.
Also known in the art are U.S. Pat. No. 4,081,004 (Harris); U.S. Pat. No. 4,537,013 (Tetenborg et al.); U.S. Pat. No. 4,566,505 (Ruf et al.); U.S. Pat. No. 5,014,493 (West); U.S. Pat. No. 5,301,492 (Kader); U.S. Pat. No. 5,375,396 (Huwelmann); U.S. Pat. No. 5,466,894 (Naef); U.S. Pat. No. 6,065,271 (Nicastro); and U.S. Pat. No. 6,776,197 (De Crane), which disclose various bag filling apparatuses and methods for packing loose material.